The invention relates to a combine harvester comprising an axial separating device for separating a crop flow picked up by the combine harvester into a plurality of partial flows, the axial separating device including means for manipulating a local concentration gradient of a partial flow output caused by the tilt of the combine harvester and method for operating thereof.
Combine harvesters comprising an axial separating device for separating a crop flow picked up by the combine harvester into a plurality of partial flows, where a partial flow composed of grain and non-grain components is fed by way of a separation surface of the axial separating device to a cleaning unit disposed downstream thereof are known. In harvesting processes that take place in a plane, a substantially uniform output of the partial flow from the axial separating device becomes established. Consequently, downstream devices such as the cleaning device are likewise loaded with crop in a uniform manner. But when harvesting is performed on a sloped hillside, the force of gravity causes harvested crop to accumulate on the downhill side when transferred from the header into the feed rake, while the concentration of crop decreases on the uphill side. This results in a crop local concentration gradient forms. This crop local concentration gradient continues as processing takes place within the combine harvester and continuously increases.
EP 1 284 098 A1 makes known a combine harvester of the initially mentioned type, which comprises an axial separating rotor for separating a crop flow into a plurality of partial flows. The partial flows contain the useful material and waste material in different concentrations. A cleaning unit is disposed downstream of the axial separating rotor, to which a partial flow composed of grain and non-grain components is fed in order to separate them from each other. The axial separating rotor is enclosed by a separation surface, which is formed of wire crating and comprises two sections having a plurality of openings. The separation surface of the axial separating rotor, which is subdivided into the two sections, comprises, in the first, upstream section thereof, a plurality of plates staggered in the circumferential direction, while the second section is formed only of wire grating in the conventional manner.
Each of the plates of the first section is pivotable about an axis that is parallel to the longitudinal axis of the axial separating rotor. To this end, the plates are mechanically coupled to one another in order to influence their pivot setting by way of a common linear actuator. To ensure that the portion of non-grain components in the partial flow output by the axial separating rotor remains small, the first section of the separation surface is closed in the crop-inlet region starting in the upstream direction in order to obtain an accumulation of grain in the outer region of the crop circulating in the axial separating rotor. The shifting of the earliest separation region in the upstream direction is controlled depending on the quantity of waste material that is separated out by way of the partial flow of useful material.
The aforementioned axial separating rotor significantly increases performance during harvesting travel in the plane, under certain harvesting conditions. But if the combine harvester begins to tilt transversely to the conveyance direction, for example, during travel along an incline, the local concentration of the partial flow output by the axial separating rotor increases on the downhill side. This occurs because the load in the header is greater on the downhill side due to the force of gravity, and therefore the separation thereof on the input side results in an additional loading of a cleaning unit disposed downstream of the axial separating rotor. The performance of the combine harvester on the sloped hillside therefore decreases.